Cisco NX-OS/IOS Interface Comparison

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This tech note outlines the main differences in interface support between Cisco® NX-OS Software and Cisco IOS® Software. Sample configurations are included for Cisco NX-OS and Cisco IOS Software for some common features to demonstrate the similarities and differences. Please refer to the NX-OS documentation on Cisco.com for a complete list of supported features.

SVI command-line interface (CLI) configuration and verification commands are not available until you enable the SVI feature with the feature interface-vlan command.

Tunnel interface command-line interface (CLI) configuration and verification commands are not available until you enable the Tunnel feature with the feature tunnel command.

Interfaces support stateful and stateless restarts after a supervisor switchover for high availability.

Only 802.1q trunks are supported, so the encapsulation command isn't necessary when configuring a layer-2 switched trunk interface. (Cisco ISL is not supported)

An IP subnet mask can be applied using /xx or xxx.xxx.xxx.xxx notation when configuring an IP address on a layer-3 interface. The IP subnet mask is displayed as /xx in the configuration and show interface command output regardless which configuration method is used.

The CLI syntax for specifying multiple interfaces is different in Cisco NX-OS Software. The range keyword has been omitted from the syntax (IE: interface ethernet 1/1-2)

When monitoring interface statistics with the show interface CLI command, a configurable load-interval can be configured per interface with the load-interval counters command to specify sampling rates for bit-rate and packet-rate statistics. The Cisco IOS Software supports the load-interval interface command, but doesn't support multiple sampling rates.

I/O modules have a locator-LED (beacon) that allows remote-hands-support personnel to easily identify a specific port. The beacon light can be enabled per interface in interface configuration mode with the beacon CLI command.

An administrator can configure port profiles as templates that can be applied to a large number of interfaces to simplify the CLI configuration process. Port profiles are "live" configuration templates, so modifications to a port profile are automatically applied to the associated interfaces. Cisco IOS uses port macros to simplify the CLI configuration process, but unlike Port Profiles they are applied one time.

The supervisor module out-of-band management ethernet port located on the supervisor module is configured with the interface mgmt 0 CLI command.

The supervisor module out-of-band Connectivity Management Processor (CMP) port is configured in the NX-OS with the interface cmp module <#> CLI command. The CMP port can also be configured by attaching to the CMP using the attach cmp CLI command.

The following list provides some additional facts about the Cisco NX-OS that should be helpful when configuring interfaces.

An interface can only be configured in 1 VDC at a time.

When assigning interfaces to a VDC on the 48 port SFP/UTP M1 series modules there are no restrictions.

When assigning interfaces to a VDC on the 32 port 10GE M1 series modules, all four interfaces in a port group must be assigned to the same VDC.

When assigning interfaces to a VDC on the 32 port 1/10GE F Series module, both ports in a port group must be assigned to the same VDC.

When assigning interfaces to a VDC on a Nexus 2248TP, all interfaces must belong to the same VDC.

One 10 GE interface per port group can be configured in dedicated mode using the rate-mode dedicated interface CLI command on the M1 series modules (The remaining three ports are disabled).

The mgmt 0 port is associated to all configured VDCs allowing TELNET/SSH and IP management applications such as SNMP to access the VDC directly. All mgmt 0 ports must be configured in the same IP subnet.

The default port type is configurable for L3 routed or L2 switched in the setup startup script. (L3 is the default port type prior to running the script)

A layer-2 switched trunk port sends and receives traffic for all VLANs by default (This is the same as Cisco IOS Software). Use the switchport trunk allowed vlan interface CLI command to specify the VLANs allowed on the trunk.

An interface configuration can be reset to its default values with the default interface <x/x> global configuration command.

The 48 port UTP M1 series module supports Time Domain Reflectometry (TDR) cable diagnostics. All 12 ports in a port group must be shutdown prior to running the test cable-diagnostics tdr interface ethernet <x/x> CLI command. The results can be verified with the show interface ethernet <x/x> cable-diagnostics-tdr command.

Configuration Comparison

The following sample code shows configuration similarities and differences between the Cisco NX-OS and Cisco IOS Software CLIs. The CLI is very similar between Cisco IOS and Cisco NX-OS Software.

Cisco IOS CLI

Cisco NX-OS CLI

Configuring a Routed Interface

interface gigabitethernet 1/1

ip address 192.168.1.1 255.255.255.0

no shutdown

interface ethernet 1/1

ip address 192.168.1.1/24

no shutdown

Configuring a Switched Interface (VLAN 10)

vlan 10

interface gigabitethernet 1/1

switchport

switchport mode access

switchport access vlan 10

no shutdown

vlan 10

interface ethernet 1/1

switchport

switchport mode access

switchport access vlan 10

no shutdown

Configuring a Switched Virtual Interface (SVI)

Cisco IOS Software does not have the ability to enable or disable SVI interfaces using the feature command.

interface vlan 10

ip address 192.168.1.1 255.255.255.0

no shutdown

feature interface-vlan

interface vlan 10

ip address 192.168.1.1./24

no shutdown

Configuring a Switched Trunk Interface

interface GigabitEthernet 1/1

switchport

switchport trunk encapsulation dot1q

switchport trunk native vlan 2

switchport trunk allowed vlan 10,20

switchport mode trunk

no shutdown

interface ethernet 1/1

switchport mode trunk

switchport trunk allowed vlan 10,20

switchport trunk native vlan 2

no shutdown

Configuring a Routed Trunk Sub-Interface

interface gigabitethernet 1/1

no switchport

no shutdown

interface gigabitethernet1/1.10

encapsulation dot1Q 10

ip address 192.168.1.1 255.255.255.0

no shutdown

interface ethernet 1/1

no switchport

no shutdown

interface ethernet 1/1.10

encapsulation dot1q 10

ip address 192.168.1.1/24

no shutdown

Configuring a Loopback Interface

interface loopback 1

ip address 192.168.1.1 255.255.255.255

no shutdown

interface loopback 1

ip address 192.168.1.1/32

no shutdown

Configuring a Tunnel Interface

Cisco IOS Software does not have the ability to enable or disable Tunnel interfaces using the feature command.

interface Tunnel 1

ip address 192.168.1.1 255.255.255.0

tunnel source 172.16.1.1

tunnel destination 172.16.2.1

no shutdown

feature tunnel

interface tunnel 1

ip address 192.168.1.1/24

tunnel source 172.16.1.1

tunnel destination 172.16.2.1

no shutdown

Configuring an Interface Description

interface gigabitethernet 1/1

description Test Interface

interface ethernet 1/1

description Test Interface

Configuring Jumbo Frames

interface gigabitethernet 1/1

mtu 9216

interface ethernet 1/1

mtu 9216

Configuring Multiple Interfaces (Examples)

interface range gigabitethernet 1/1-2

or

interface range gigabitethernet 1/1, gigabitethernet 2/1

interface ethernet 1/1-1

or

interface ethernet 1/1, ethernet 2/1

Configuring Port Profiles

Cisco IOS Software does not have the ability to configure port profiles.

port-profile type ethernet Email-Template

switchport

switchport access vlan 10

spanning-tree port type edge

no shutdown

description Email Server Port

state enabled

interface ethernet 2/1-48

inherit port-profile Email-Template

TDR Cable Diagnostics

test cable-diagnostics tdr interface gigabitethernet 1/1

test cable-diagnostics tdr interface etherent 1/1

Configuring the Interface Locator-LED (Beacon)

Cisco IOS Software does not have the ability to enable a located-led per interface.

interface ethernet 1/1

beacon

Configuring a Nexus 2000(FEX) Host Interface

Cisco IOS Software does not have the ability to connect a Nexus 2000(FEX).

interface ethernet 101/1/1

Verification Command Comparison

The following table lists some useful show commands for verifying the status and troubleshooting an interface.

Cisco NX-OS Interface

Cisco IOS Software Interface

Command Description

show interface

show interface

Displays the status and statistics for all interfaces or a specific interface